Research will be performed in which the various regulatory properties of the pyruvate and the branched chain alpha-keto acid dehydrogenase multienzyme complexes in isolated rat liver mitochondria and in the isolated perfused rat liver will be delineated. Primary considerations will be: 1) the interaction between various regulatory effectors of the pyruvate dehydrogenase and its kinase and phosphatase; 2) the effect of alpha-agonists on the regulation of pyruvate dehydrogenase; and 3) the mechanism of regulation of the branched chain alpha-keto acid dehydrogenase multienzyme complexes.